In packet transmission networks, networks using radio lines have a small transmission capacity for one radio line. Therefore, there are cases where a plurality of radio lines are bundled up and used as one line in order to secure a proper transmission capacity. In the case where radio lines are bundled up in this way, when the radio line status has changed and hence the transmission band has changed, it is necessary to carry out data distribution and band control in accordance with the radio line status. Note that the bundling of a plurality of radio lines can also be expressed as “bonding radio lines”.
Patent literature 1 discloses a configuration of a radio relay apparatus that performs AMR control. The radio relay apparatus disclosed in Patent literature 1 can automatically change the radio modulation method for the wireless section between the radio relay apparatus and the transfer-source radio relay apparatus when the radio modulation method for the wireless section between the radio relay apparatus and the transfer-destination radio relay apparatus is changed by the AMR control.